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Explore the intricate process of cell division and reproduction, from DNA replication to chromosome separation in mitosis. Learn how prokaryotic and eukaryotic cells multiply and understand the significance of homologous chromosomes.
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Chapter 4 Section 3 Mitosis
The Cell Cycle • Your body produces millions of cells in order for you to grow and to replace cells that have died • Ex. Stomach lining is replaced every few days
The Life of a Cell • Cell Cycle • The life cycle of a cell • Begins when the cell is formed and ends when the cell divides and forms new cells
Before a cell divides • It must first make a copy of its DNA • DNA contains the information that tells a cell how to make proteins. • DNA is organized into chromosomes
Making More Prokaryotic Cells • Prokaryotic cells and their DNA are relatively simple • Bacteria have ribosomes and a single circular molecule of DNA • Therefore division for bacteria is simple
Binary Fission • Splitting into 2 parts • Each resulting cells contain one copy of the DNA
Binary Fission http://diverge.hunter.cuny.edu/~weigang/Images/06-11_binaryfission_1.jpg
Eukaryotic Cells and Their DNA • Larger and more complex than prokaryotic cells • Because of this, eukaryotic cells have MORE DNA • Chromosomes contain DNA and Proteins
Eukaryotic Cells • Number of chromosomes differs from one kind of organism to the next • Number has nothing to do with the complexity of the organism
Fruit Fly- 8 chromosomes • Potato- 48 chromosomes • Humans- 46 chromosomes
Homologous Chromosomes • Chromosomes with matching information • Pairs
Making More Eukaryotic Cells • 3 main stages of cell cycle • Stage 1 or Interphase - cell grows and copies its organelles and chromosomes, DNA and protein strands are loosely coiled pieces of thread
Interphase continued • After the chromosomes are duplicated, the two copies are called CHROMOTIDS which are held together at a region called a CENTROMERE • Chromatids coil and condense into an X shape
Mitosis, Stage 2 • Chromatids separate • Mitosis – process of chromosome separation • Two new nuclei are made • Each new cell receives a copy of each chromosome
Stage 3 of Cell Cycle • Cytokinesis • The cell divides and produces 2 new cells that are identical to the original cell